INSPIRE: Exploring living system responses to quantum states of light

该项目由数学和物理科学局（MPS）物理（PHY）和化学（CHE）部门的以下计划以及社会和行为与经济科学局（SBE）的行为和认知科学（BCS）部门共同资助，由综合活动办公室共同资助：MPS/PHY/原子，分子和光学物理学-实验，MPS/PHY/生命系统物理学，MPS/CHE/生命过程化学，SBE/BCS/感知，行动和认知计划以及SBE多学科活动办公室。 该项目将测试生物如何探测光的极限，并研究量子力学定律如何应用于生物系统。单光子（光的单个粒子）将用于研究人类视觉系统和光敏细菌。在人类视觉系统中，该项目将通过使用一次创建一个光子的方法来测试人类观察者的视力，从而确定人类是否可以看到单个光子（这是心理学中的一个长期问题）。该项目还将研究人类观察者在量子力学允许的叠加状态下探测到光子时所看到的东西-这是一种同时在两个地方的状态。还将使用单光子研究光敏细菌，以了解光探测的极限以及量子定律在不同生物系统中的可能影响。除了推进我们对生物如何检测和使用光的知识之外，这项研究还可以帮助我们理解为什么光子等粒子表现出奇怪的量子行为，如叠加，而我们周围熟悉的世界表现出不同的行为。让量子效应为人类所感知，也将具有广泛的公众吸引力，并可能成为学生和公众了解量子物理的门户。为了产生单光子，该项目将使用一种基于自发参数下转换的著名的预示单光子源设计。505 nm和440 nm的单光子将用于人类和E. coli中表达。为了确定人类是否能看到单个光子，观察者将完成一系列试验，在这些试验中，他们必须选择刺激光子是出现在他们视野的左侧还是右侧。如果观察者能够以统计上大于50%的准确度选择左或右，这就是他们可以看到单光子的有力证据。还将开发一种EEG应急刺激传递方法，以提高检测的可能性。如果单光子视觉得到证实，随后的实验将尝试用人类观察者取代一个单光子探测器来测试量子非定域性。最后，为了测试叠加态的感知，观察者将看到左右两个点的光子的经典混合物，以及左右两个点叠加的光子。观察者选择左和右的频率将在两种情况下进行比较，任何意想不到的差异都表明偏离了标准量子力学。为了研究趋光性细菌（对光有反应的细菌），个体E。将大肠杆菌细胞固定在IR光阱中并用单光子刺激。在已建立的技术中，可以通过用捕获光束跟踪细胞的游泳和翻滚行为来测量细胞的响应。其他物种将在以下实验中进行研究，包括光合作用的球形红细菌。

This project is jointly funded by the following programs in the Divisions of Physics (PHY) and Chemistry (CHE) of the Directorate for Mathematics and Physical Sciences (MPS), and the Division of Behavioral and Cognitive Sciences (BCS) of the Directorate for Social and Behavioral and Economic Sciences (SBE), with co-funding from the Office of Integrative Activities: MPS/PHY/Atomic, Molecular, and Optical Physics--Experiment, MPS/PHY/Physics of Living Systems, MPS/CHE/Chemistry of Life Processes, SBE/BCS/Program on Perception, Action, and Cognition and the SBE Office of Multidisciplinary Activities. This project will test the limits of how living things detect light and study how the laws of quantum mechanics apply to biological systems. Single photons (individual particles of light) will be used to study both the human visual system and light-sensitive bacteria. In the human visual system, this project will determine whether humans can see a single photon (a longstanding question in psychology) by using a method of creating one photon at a time to test the vision of human observers. This project will also investigate what human observers see when they detect a photon in a superposition - a state of being in two places at the same time - which is allowed by quantum mechanics. Light-sensitive bacteria will also be studied using single photons, to understand the limits of light detection and the possible effects of quantum laws in a different biological system. In addition to advancing our knowledge of how living things detect and use light, this research might help us understand why particles such as photons show strange quantum behavior such as superposition, while the familiar world around us behaves differently. Making quantum effects available to human perception would also have broad popular appeal, and could be a gateway for students and the public to learn about quantum physics.To produce single photons, this project will use a well-known heralded single-photon source design based on spontaneous parametric downconversion. Single photons at 505 nm and 440 nm will be used for experiments with humans and E. coli, respectively. To determine whether humans can see single photons, observers will complete a series of trials in which they must choose whether the stimulus photon appeared on the left or the right side of their visual field. If observers are able to choose left or right with accuracy statistically greater than 50%, this is strong evidence that they can see single photons. An EEG-contingent stimulus delivery method will also be developed to improve the likelihood of detection. If single-photon vision is confirmed, a subsequent experiment will attempt a test of quantum nonlocality with a human observer replacing one single-photon detector. Finally, to test perception of superposition states, observers will be presented with both a classical mixture of photons at the left and right spots, and photons in a superposition of left and right. The observer's frequency of choosing left and right will be compared between the two cases, with any unexpected difference suggesting a deviation from standard quantum mechanics. To study phototactic bacteria (which move in response to light), individual E. coli cells will be immobilized in an IR optical trap and stimulated with single photons. In an established technique, the response of the cells can be measured by tracking their swimming and tumbling behavior with the trapping beam. Other species will be studied in following experiments, including photosynthetic Rhodobacter sphaeroides.